package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWoker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.Redisson;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Slf4j
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {
    @Resource
    private ISeckillVoucherService seckillVoucherService;

    //订单id生成器
    @Resource
    private RedisIdWoker redisIdWoker;

    @Resource
    private RedissonClient redissonClient;

    private IVoucherOrderService proxy;

    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    private BlockingQueue<VoucherOrder> ordersTask = new ArrayBlockingQueue<>(1024*1024);
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();
    private class VocherOrderHandler implements Runnable {
        @Override
        public void run() {
            while (true) {
                try {
                    VoucherOrder voucherOrder = ordersTask.take();
                    handleVocherOrder(voucherOrder);
                } catch (InterruptedException e) {
                    log.error("处理订单异常",e);
                }
            }
        }
    }

    private void handleVocherOrder(VoucherOrder voucherOrder) {
        Long userId = voucherOrder.getUserId();
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        boolean isLock = lock.tryLock();
        if (!isLock){
            log.error("获取锁失败");
        }
        try {
            proxy.addVoucherOrder(voucherOrder);
        } finally {
            lock.unlock();
        }
    }

    @PostConstruct
    private void init(){
        SECKILL_ORDER_EXECUTOR.submit(new VocherOrderHandler());
    }

    @Override
    public Result seckillVoucher(Long voucherId){
        Long userId = UserHolder.getUser().getId();
        //执行lua脚本
        Long result = stringRedisTemplate.execute(
                SECKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString()
        );

        //判断结果是否为0
        int r = result.intValue();
        if (r!=0){
            return Result.fail(r==1?"库存不足":"不能重复下单");
        }

        VoucherOrder voucherOrder = new VoucherOrder();

        //订单id
        long orderId = redisIdWoker.nextId("order");
        voucherOrder.setId(orderId);

        //用户id
        Long userID = UserHolder.getUser().getId();
        voucherOrder.setUserId(userID);

        //代金券id
        voucherOrder.setVoucherId(voucherId);

        //保存到阻塞队列
        ordersTask.add(voucherOrder);
        proxy = (IVoucherOrderService) AopContext.currentProxy();
        return Result.ok(orderId);
    }

//    @Override
//    public Result seckillVoucher(Long voucherId) {
//        //查询优惠券
//        SeckillVoucher seckillVoucher = seckillVoucherService.getById(voucherId);
//
//        //查询秒杀是否开始
//        if (seckillVoucher.getBeginTime().isAfter(LocalDateTime.now())){
//            return Result.fail("秒杀尚未开始！");
//        }
//
//        //查询秒杀是否结束
//        if (seckillVoucher.getEndTime().isBefore(LocalDateTime.now())){
//            return Result.fail("秒杀已结束！");
//        }
//
//        //判断库存是否充足
//        if (seckillVoucher.getStock()<1){
//            return Result.fail("库存不足！");
//        }
//
//        Long userId = UserHolder.getUser().getId();
//
////        //悲观锁
////        synchronized (userId.toString().intern()){
////            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
////            return proxy.addVoucherOrder(voucherId);
////        }
//
//        //redisson获取锁释放锁
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        boolean isLock = lock.tryLock();
//        if (!isLock){
//            return Result.fail("不允许重复下单");
//        }
//        try {
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.addVoucherOrder(voucherId);
//        } finally {
//            lock.unlock();
//        }
//
//
//    }

    @Transactional
    public void addVoucherOrder(VoucherOrder voucherOrder) {
        //一人一单
        Integer count = query().eq("user_id", UserHolder.getUser().getId())
                .eq("voucher_id", voucherOrder.getVoucherId()).count();
        if (count>0){
            log.error("用户已经购买过优惠券了！");
            return;
        }

        //扣减库存
        boolean updateSuccess = seckillVoucherService.update().setSql("stock = stock - 1")
                .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock",0).update();
        if (!updateSuccess){
            log.error("库存不足！");
            return;
        }

        //写入数据库
        save(voucherOrder);

    }
}
